Charles Darwin was probably correct about the effects of inbreeding in his family, according to a new study in BioScience.

Darwin demonstrated the phenomenon of inbreeding depression in many plants, and was aware of research into the effects of marriage between relatives on the health of resulting children. He feared that his marriage might have been responsible for some of his children's health problems.

The British Naturalist married his first cousin, Emma Wedgwood, and his mother, Susannah Wedgwood, was the daughter of third cousins.

The new study of 25 families, including 176 children, found a statistical association between child mortality and the inbreeding coefficient of individuals in the Darwin/Wedgwood dynasty. The researchers suggest that the expression of deleterious genes "produced by consanguineous marriages could be involved in the high childhood mortality experienced by Darwin progeny."

Furthermore, three of Darwin's six children with long-term marriages left no offspring. Unexplained infertility may also be a consequence of a consanguineous marriage.

Three of Charles Darwin's 10 children died before reaching adulthood, one from childhood tuberculosis at age 10 and one from unknown causes as an infant. A third child, who died in infancy of scarlet fever, appears in a photograph to have developmental abnormalities. Inbreeding is an important risk factor in a number of human diseases, including infectious diseases.



Citation: Tim M. Berra, Gonzalo Alvarez, Francisco C. Ceballos, 'Was the Darwin/Wedgwood Dynasty Adversely Affected by Consanguinity?', BioScience, May 2010 60(5); doi:10.1525/bio.2010.60.5.7